The number of echoes combined into a single image or image set in multiple echo imaging sequences or echo-train techniques such as rapid acquisition with relaxation enhancement (RARE), fast-spin echo (FSE), and turbo spin-echo (TSE). In RARE imaging, the ETL typically equals the acceleration factor.
As for tooth pain, it is caused by a reaction of the nerves inside a tooth's pulp chamber with the severity dependent upon the type and degree of the stimulus. What follows are some examples of symptoms you may be feeling and their possible causes.
Toothaches and jaw pain are common but can have different sources. Learn more from the experts at WebMD. Tooth sensitivity is tooth discomfort in one or more teeth that is triggered by hot, cold, sweet, or sour foods and drinks, or even by breathing cold air. The pain can be sharp, sudden, and shoot deep into the nerve endings of your teeth.